Strapping tools



Aug. 18, 1970 B. DUNN v 3,524,480

swmrrme TOOLS Filed April 8, 1968 3 SheetsSheet l 9 I F Y hivxx [NVENTOR BENJAMIN DUNN ATTORNEYS B. DUNN STRAPPING TOOLS I5 Sheets-Sheet 2 Filed April 8, 1968 Au 18,1910 Y B. DUNN 3,524,480

STRAPPING TOOLS Filed April 8, 1968 5 Sheets-Sheet 3 FIG. 4

42 w 41 M4 i g 5 W E ii} United States Patent 3,524,480 STRAPPING TOOLS Benjamin Dunn, Newington, Conn., assignor to The Stanley Works, New Britain, C0nn., a corporation of Connecticut Filed Apr. 8, 1968, Ser. No. 719,321 Int. Cl. B21f 9/00 US. Cl. 140-934 9 Claims ABSTRACT OF THE DISCLOSURE A powered strapping tool includes a stationary tensioning unit and a strap sealing and shearing mechanism cam driven by a single control handle between a retracted and a sealing position. The single handle also controls operation of a valve regulating fluid flow to the tensioning unit so that the unit is started at the same time the handle operatively moves the sealing and shearing apparatus into its sealing position.

The present invention generally relates to tools adapted for strap tensioning, sealing and severing operations and is particularly directed to a new and improved control mechanism for such tools.

A principal object of this invention is to provide a new and improved control mechanism for powered strapping tools which includes a single control handle for operatively positioning the sealing and shearing mechanism of the tool and at the same time controlling the tensioning operation thereof, all in a smooth, simplified and eflicient manner.

Another object of the invention is to provide a control mechanism for a powered strapping tool of the type described which operatively positions the sealing head of the tool and simultaneously actuates the tensioning unit of the tool during one uninterrupted motion of the control handle.

.Still another object is to provide a new and improved control mechanism for a fluid powered strapping tool which utilizes the movement of the control handle not only to shift the position of the sealing jaws of the tool but also to control the flow of fluid to the strap tensioning unit of the tool. Included in this object is the provision for a control that precludes energization of the tensioning unit until the sealing head of the tool is operatively positioned.

An additional object is to provide a simplified, more easily operated control mechanism for a fluid powered strapping tool including a single control lever for operating a retractable, fluid powered sealing mechanism and a stationary fluid powered tensioning unit.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a side elevation, partly in section, showing a portable powered strapping tool incorporating an embodiment of the control mechanism of the present invention;

FIG. 2 is an enlarged plan view, partly in section, illustrating the control mechanism of FIG. 1 in greater detail;

FIG. 3 is a sectional view taken along line 33 of FIG. 2;

3,524,480 Patented Aug. 18, 1970 FIG. 5 is a sectional view taken along line 5--5 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in greater detail wherein like reference numerals indicate like parts throughout the several figures, an embodiment of the present invention is shown incorporated in a fluid powered strapping tool 50 for tightening and sealing a length of strapping about a suitable article, such as the package 3. The strapping tool 50 includes a stationary frame member 13 of gen erally L-shaped configuration having a base 32 overlying a free end of the strap 4 and an angularly disposed support 36, frequently referred to as the duckbill, upstanding from the base and adapted for slidably mounting a control mechanism, generally designated 40, and a strap sealing mechanism 56. The frame member 13 additionally securely and fixedly mounts a tensioning unit 54 including a tensioning wheel 30 which overlies and cooperates with the top surface 34 of the base 32 for tightening the strap about the package prior to the sealing and severing thereof by the mechanism 56. As best shown in FIGS. 2 and 4, the support or duckbill 36 is provided along the full length of each side thereof with projecting track forming flanges 42 which are cooperatively engaged by shoulders 44 of the control mechanism 40 to facilitate reciprocable sliding movement of the mechanisms 40 and 56 during pivotal movement of a manual control lever 1 between its operative and rest positions, respectively, illustrated by the full and phantom line positions shown in FIG. 1.

Referring now to the embodiment illustrated in FIGS. 1-3, the control lever 1 of mechanism 40 is secured to one end of a control spindle 9 which mounts on its opposite end a concentric cam 14 and a projecting eccentric pin 15. As shown, the pin 15 is operatively positioned within a central, transversely extending slot 16 in the upstanding duckbill 36 so that rotation of the lever 1 will cause the spindle 9 and coaxial cam 14 to be raised and lowered relative to the stationary frame member 13. A cam follower plate 10 confined between the duckbill 36 and a fluid control valve housing 17 circumscribes the cam 14 and is displaced relative to the frame 13 by the cam 14 as the lever 1 is rotated. The plate 10 is also fixedly connected to a pair of guides 11 located on each side of the duckbill 36 and to the valve housing 17 for movement as a single unit by the cam 14. The guides 11 which carry the flange contacting shoulders 44 prevent lateral movement of the cammed unit as lever 1 is rotated, thus causing pin 15 to slide laterally within slot 16 as the unit is raised and lowered. Additionally, the guides 11 are secured to the sealing mechanism 56 for driving the latter between its respective rest and operating positions as lever 1 is rotated from its vertical to its horizontal position.

Referring particularly to FIGS. 2 and 3, it will be ap preciated that control mechanism 40 of the invention not only raises and lowers the sealing mechanism 56 but also controls the operation of the tensioning mechanism 54 so that whenever the sealing mechanism 56 is moved to its lowered or sealing position the motor of the tensioning unit is automatically energized, thus eliminating the separate, manual operation of sealing and tensioning units as heretofore required. In addition to the pin 15 and the apparatus therewith which positions the mechanism 56, the embodiment of the control mechanism 40 illustrated in FIGS. 1-3 includes a circular cam element 19 fixedly mounted on the control spindle 9 eccentrically of the spindle axis for rotation with the spindle. A valve rod 18 projects from the valve housing 17 and contacts the cam 19 thereby sensing the rotational movement of the spindle 9 and suitably controlling the operation of the valve. The valve rod 18, which bears against and follows the cam 19, is mounted for reciprocable movement in a chamber 24 of the valve housing 17 and extends therein a sufficient distance to form a valve gate for the fluid outlet port 22 communicating with chamber 24. The outlet port 22 in turn is connected with the tensioning unit 54 through a suitable conduit 22a. Thus, it will be appreciated that when the lever 1 is in the position shown in FIG. 2, the valve rod 18 is in its fully retracted position permitting communication between chamber 24 and outer port 22 and flow of operating fluid to the tensioning unit 54.

A supply of air from a suitable source enters valve housing 17 through the air inlet port 21 and flows therefrom to the chamber 24 via a passage 25 in which an adjustable throttle device, such as the set screw 23, is installed. The passage 25 leads into the chamber 24 well upstream of the outlet port 22 so that pressurized air entering inlet port 21 will bear against the valve rod 18 driving it into continuous following abutment with the cam 19 as the handle is swung toward the position illustrated in FIG. 2. On the other hand, as the handle is swung out of the position shown, the valve rod 18 is slowly cammed by cam 19 toward passage 25 until it crosses the mouth of outlet port 22, closing oil the air flow to the tensioning unit.

The normal operation of the tensioning unit 54 is such that as a preset strap tension is reached, the wheel 30 will merely hold the strap despite the fact that the unit has not been deactivated. Accordingly, an operator handling the tool 50 utilizing the invention need not swing the handle from its operative position, thereby raising the sealing mechanism 56 and closing off the flow of air to the tensioning unit, until it is convenient to do so.

An alternative embodiment of the invention is shown in FIGS. 4 and 5, and is readily utilized by the tool 50. The lever 1 is swung to shift the sealing mechanism 56, as in the embodiment shown in FIGS. l-3, by substantially the same means used therein, including the eccentric pin 15 movable within the aperture 16 of the upright duckbill 36 and the cam 14 operatively connected for reciprocably moving the sealing mechanism 56. However, in this embodiment, a single combined cam following unit and valve body 100 replaces the plate 10, guides 11 and valve housing 17 of FIGS. l-3. The unit 100 is provided with shoulders 144 similar to shoulders 44 on guides 11 for cooperating with flanges 42 in restraining lateral movement of the unit 100. Additionally, unit 100 is directly fixed to the mechanism 56 so that as the lever 1 is rotated, the mechanism 56 is vertically displaced relatively to the frame member 13.

In order to provide for energizing the tensioning unit when the mechanism 56 reaches its lowered position, the upright duckbill 36 fixedly mounts a transversely extending pin 172 which-in turn carries a depending valve rod 180 disposed within a chamber 240 of the combined follower unit and valve body 100. Pressurized air entering the valve. through an inlet port 210 is regulated by way of an adjustable throttling device 230 within inlet passage 250 and, when rod 180 is retracted, it passes through passage 250 into chamber 240 and onward to the tensioning unit 54. Thus, as the handle 1 is moved to the position shown in FIG. 4, cam 14 will lower the combined unit and valve body 100 thereby opening the valve gate between chamber 240 and passage 250. As can be appreciated the stationary valve rod 180 thereby permits air flow between the inlet port 210 and the tensioning unit 54 in substantially the same manner as mentioned with respect to FIGS. 1-3.

Thus, from the foregoing detailed description, it can be seen that the improved control mechanism of the present invention requires only one uninterrupted motion of the lever 1 to change the position of thesealing mecha As will be apparent to persons skilled in thelart, vari ous modifications and adaptations of the structure abovedescribed willbecome readily apparent without departure from the spirit and scope of the invention, the scope, of which is defined in the appended claims v i I claim:

v1. In a strapping tool having a strap tensioning unit and a strap sealing mechanism movable between retracted and sealing positions, the combination comprising a tool control mechanism including a single control actuator movable between rest and operative, positions for driving the sealing mechanism and. for controlling the operation of the tensioning unit, said control mechanism including a drive member movable with said actuator for directly driving the sealing mechanism relative to the ten.- sioning unit between its retracted and sealing positions, said control mechanism including tensioning control means responsive to movement of the control actuator into its operative position for activating the tensioning unit simultaneously with the movement of the sealing mechanism into its sealing position. v

2. A strapping tool as claimed in claim 1 wherein the tensioning unit is fluid operated and the tensioning control means includes a valve regulating fluid flow to said tensioning unit, said valve having a flow control gate controlled by the actuator for movement between closed and open positions.

3. A strapping tool as claimed in claim 2 wherein the tensioning control means includes cam means mounted for operation with said control actuator for positioning the flow control gate in its open position as the actuator moves into its operative position.

4. A strapping tool as claimed in claim 1 wherein the drive member includes cam means operable by the actuator for moving the sealing mechanism relativeto the tensioning unit between its retracted and sealing positions, said control mechanism having guide means restricting lateral movement of the sealing mechanism.

5. A strapping tool as claimed in claim 4 wherein the control mechanism includes a control gate for controlling actuation of the tensioning unit, said control gate being operative in response to the operation of the cam means.

6. The strapping tool of claim 1 wherein the tensioning unit is fluid operated and the tensioning control means includes cam means controlled by the single control actuator and a valve having a valve gate operative by the cam means between open and closed positions for controlling the flow of operating fluid to the tensioning unit.

7. The strapping tool of claim 6 wherein the drive member includes a first cam for driving the valve in unison with the sealing mechanism.

8. The strapping tool of claim 7 wherein the cam means includes a second cam mounted on the single control actuator independently of the valve for moving the valve gate between its open and closed positions.

9. The strapping tool of claim 7 including a stationary valve rod, said valve being movable relative thereto for opening and closing the valve gate.

LOWELL A. LARSON, Primary Examiner 

